STUDIES IN LAKE AND STREAMSIDE VEGETATION 



137 



the lake through its outlet. The fluctuation in the level of the lake 

 from year to year and from season to season is slight and does not 

 seem to be of much importance in its relation to the rate of filling. 



Shore and Bottom. — Redrock Lake measures about 180 meters 

 (590 ft.) across from east to west and 120 meters (394 ft.) across from 



Lake 



10 M 



I2M. fcM. 3M. HM. 20M E. 



Fig. 2.— East- West Profile of Redrock Lake 

 The greater width of the sedge and shrub zones on the west is accounted for by the 

 fact that there is a considerable amount of seepage water through the low aspen-covered 

 moraine from the wet meadow to the west. The dry-forest opening on the east of the 

 lake is discussed under the head of Arenaria Associations in the account of zonation. 



north to south. It varies in depth from a few centimeters to 1.5m. 

 (6 inches to 4 ft.). Large morainal boulders project above the water 

 level in places. The west two-thirds of the lake has a mud bottom; 



LaKc 



Cave* S^ 1 



3M. 8M. 3DM1M. 



Fig. 3. — North-South Profile of Redrock Lake 

 The moraine on the south is relatively much steeper than the one on the north. While 

 the crest of the north moraine is shown in the figure, the crest of the moraine on the south 

 extends beyond the limits of the figure and is much higher than is shown. The 

 steep south moraine furnishes a great amount of seepage water to the lake and the run-off 

 brings wash material to the lake edge; these conditions, along with the fact that the lake 

 shore here is well shaded, account for the much wider zones on the south than on the north 

 side of the lake. The north-bounding moraine is low and has a gradual slope to the lake; 

 hence there is an accumulation of but little wash material about the lake edge. Further- 

 more the shore is well exposed to the sun and soon dries out. 



here we find patches of water lilies. The remainder of the lake-bottom 

 is stony and covered over with a fine layer of silt. 



Around the edge of the lake is a marginal rim, in some places . 6 m. 



